Volunteers have formed a vital part of British ground forces for hundreds of years. Usually raised during times of crisis or perceived threat, early volunteer units usually comprised infantry, artillery and yeomanry.

Yeomanry units were mounted and formed from gentleman farmers and tenants. One such unit, the Castlemartin Yeomanry Cavalry (later to become the Pembroke Yeomanry) earned the only battle honour awarded to a British Army unit for an action on British soil, when it repelled the last invasion of Great Britain in February 1797.

Formation of the Territorial Force
In 1907 Parliament passed legislation which saw the consolidation of the yeomanry and volunteers into the Territorial Force. The first units were stood up on 1st April 1908, and this date is accepted as the birth of what we know today as the Territorial Army.
The Territorial Force was mobilised in August 1914, its soldiers fighting alongside, and indistinguishable from, the Regular Army. Upon demobilisation in 1918 Territorial Force units were disbanded, but were reconstituted in 1920 as the part-time Territorial Army.

The Territorial Army in 1939
As war clouds loomed over Europe in the early months of 1939, the Government authorized the ‘duplication’ of all Territorial Army units, thereby doubling the size of the TA.
On the outbreak of hostilities in September 1939, the Territorial Army was mobilized and its units absorbed into the British Army. When the Army demobilised in 1946 the TA was temporarily suspended, but was reconstituted in 1947as a part-time reservist force similar to its pre-1939 structure.

The Cold War Years
During the 1950s and 1960s the Government allowed the Territorial Army to become seriously under-manned and poorly-equipped. In 1967 a poorly-advised and heavy-handed attempt at reinvigorating the reserves led to a virtual abolition of the regimental system among the reserves.
Realising the error of its ways, the government set out in 1971 to increase the size of the reserves, creating many new battalions. Subsequent expansions and reorganizations over the following 20 years meant that, by the early 1990s, the regimental system was almost totally re-established.
Throughout this period of fluctuating fortunes, the Territorial Army was never regarded as a particularly useable or effective force, either by the Government of the day or by the Regular Army. With the image of a ‘force of last resort’, its role was, at least unofficially, seen as home defence.

Recent cutbacks
In 1998 the Labour Government announced what it called the ‘Strategic Defence Review’, which would make the Army more relevant and effective in meeting the demands of the post-Cold War era and the 21st century.
The Territorial Army was the hardest-hit and within it, the infantry suffered most with 87 companies in 33 battalions reducing to 67 companies in 15 battalions. While the measures allowed for at least one company from each of the 33 battalions to survive to continue their regiments' identities, the result was that thousands of experienced and loyal personnel had their service terminated.

A New Purpose
The final years of the 1990s and the turn of the Millennium saw the Territorial Army assume a more high-profile role. As the Regular Army became increasingly engaged in overseas operations, the TA moved from being a ‘force of last resort’ to become the ‘reserve of first choice’ in supporting the Regulars. Some 6900 personnel were mobilised for Operation TELIC, the invasion of Iraq, and the TA continues to provide around 1,200 troops each year to support the Regular Army in Iraq, Afghanistan and the Balkans.
In 2004 the Government announced a radical restructuring of the Army, leading to the realignment of the TA as reserves of the regular regiments. Under TA Rebalancing, 15 TA infantry battalions were reduced to 14, but the overall strength of the force remained the same.